Patient and surgical factors affecting procedure duration and revision risk due to deep infection in primary total knee arthroplasty

Associations of parecoxib and other variables with recovery and safety outcomes in total knee arthroplasty: insights from a retrospective cohort study

Background

Early mobilization post-total knee arthroplasty (TKA) significantly affects patient outcomes. While parecoxib is known to reduce postoperative pain and morphine use with a favorable safety profile, its impact on mobilization timing post-TKA remains uncertain. This retrospective study aims to assess parecoxib's influence on postoperative mobilization timing in TKA patients without compromising safety.

Methods

This study included unilateral TKA patients treated for primary knee osteoarthritis under general anesthesia. We divided the study period into two intervals, 2007-2012 and 2013-2018, to evaluate temporal differences. Both the control group and parecoxib group received standard postoperative oral analgesics and as-needed intramuscular morphine. The control group did not receive parecoxib, while the parecoxib group did. Primary outcomes compared postoperative complications and mobilization timing between groups, with secondary outcomes including length of hospital stay (LOS), Visual Analog Scale (VAS) scores for pain, as-needed morphine use, and postoperative nausea/vomiting.

Results

Parecoxib did not increase postoperative complications. Unmatched comparison with patients in controlled group found that patients in parecoxib group had significantly shortened mobilization time (2.2 ± 1.1 vs. 2.7 ± 1.6 days, P < 0.001) and LOS (6.7 ± 2.5 vs. 7.2 ± 2.1 days, P = 0.01). Multivariate analysis linked parecoxib use with faster mobilization (β = -0.365, P < 0.001) but not LOS. Males showed increased mobilization time and LOS compared to females during the period of 2007-2018, but gender had no significant association with LOS during the period of 2013-2018. The 2013-2018 period saw significant reductions in both mobilization time and LOS. Use of a tourniquet and local infiltration analgesia showed no significant impact. ASA classification 1-2 was positively associated with faster mobilization but not LOS. Longer operation times were linked to delayed mobilization and increased LOS.

Conclusion

In this study, intravenous parecoxib injection, female gender, and shorter OP time had consistent positive association with shorter time to mobilization after individual multivariate analysis in 2 different period. The use of parecoxib had consistent no significant association with LOS. Only shorter OP time was consistent positive associated with shorter LOS.

Comparison of Pneumonia and Major Complications After Total Joint Arthroplasty With Spinal Versus General Anesthesia: A Propensity-matched Cohort Analysis

INTRODUCTION

Spinal anesthesia (SA) allows total joint arthroplasty to be done while minimizing opioids and systemic anesthetic agents compared with general anesthesia (GA). SA has been associated with shortened postoperative recovery; however, the relationship between SA, major postoperative complications, and pneumonia (PNA) remains unclear.

METHODS

Patients in a large, national database who underwent total hip arthroplasty or total knee arthroplasty from 2010 to 2020 were identified. 1:1 propensity score matching was used to create matched groups of patients who underwent SA and GA. The groups were matched by age, sex, chronic obstructive pulmonary disease, smoking status, Charlson Comorbidity Index, and American Society of Anesthesiology (ASA) classification. 1:1 matching was also done among the ASA classifications as a subanalysis.

RESULTS

Overall, equally matched groups of 217,267 patients who underwent SA versus GA were identified. 850 patients (0.39%) developed postoperative PNA after GA versus 544 patients (0.25%) after SA ( P < 0.001). The risk of major complications was 6,922 (3.2%) in the GA group and 5,401 (2.5%) in the SA group ( P < 0.001). Similarly, the risk of unplanned postoperative reintubation was higher (0.18% versus 0.10%, P < 0.001) and mortality was higher (0.14% versus 0.09%, P < 0.001) in the GA group than in the SA group. In ASA 1 to 3 patients, the risk of PNA was 0.08% to 0.21% higher with GA than with SA. In ASA 4 patients, the risk of PNA was 0.42% higher in SA than in GA (1.92% versus 1.5%, P < 0.001) and the mortality rate was nearly doubled in GA than in SA (1.46% versus 0.77%, P = 0.017).

DISCUSSION

Overall, GA was associated with a small but markedly higher rate of major complications, mortality, and PNA than SA in patients undergoing total joint arthroplasty when matching for differences in comorbidities. ASA 4 patients experienced the greatest increase in absolute risk of mortality with GA versus SA.

Staged Extra-Articular Deformity Correction in the Setting of Total Knee Arthroplasty

Background

Extra-articular lower-leg deformities mandate unique considerations when planning total knee arthroplasty (TKA). Poor limb alignment may increase perioperative complications and cause early implant failure. This study reports on the safety and efficacy of staged, extra-articular deformity correction about the knee in the setting of osteoarthritis and TKA.

Methods

A retrospective review was conducted from December 2007 to December 2019 identifying 30 deformities in 27 patients (average age: 52.7 years; range 31-74) who underwent staged surgical correction of extra-articular deformity in preparation for TKA. Patient demographics, surgical details, clinical and radiographic measurements, severity of knee arthritis, and complications were collected.

Results

There were 17 femur and 12 tibia deformities. There was an average improvement of 14.7° of deformity measured in the coronal plane and 12.7° of deformity in the sagittal plane in the femur and 13.5° in the coronal plane and 10.3° in the sagittal plane in the tibia. Leg length discrepancies improved by 26 mm on average (1-100 mm). After an average 3.1-year follow-up, 12 out of 27 patients proceeded with primary or revision TKA. There were no cases of blood transfusion, nerve palsy, or compartment syndrome, and all patients achieved bony union.

Conclusions

Staged, extra-articular deformity correction is a safe and effective approach to improve limb alignment in the setting of knee osteoarthritis and TKA.

Incidence, Microbiological Studies, and Factors Associated With Prosthetic Joint Infection After Total Knee Arthroplasty

Importance

Despite the frequency of total knee arthroplasty (TKA) and clinical implications of prosthetic joint infections (PJIs), knowledge gaps remain concerning the incidence, microbiological study results, and factors associated with these infections.

Objectives

To identify the incidence rates, organisms isolated from microbiological studies, and patient and surgical factors of PJI occurring early, delayed, and late after primary TKA.

Design, Setting, and Participants

This cohort study obtained data from the US Department of Veterans Affairs (VA) Corporate Data Warehouse on patients who underwent elective primary TKA in the VA system between October 1, 1999, and September 30, 2019, and had at least 1 year of care in the VA prior to TKA. Patients who met these criteria were included in the overall cohort, and patients with linked Veterans Affairs Surgical Quality Improvement Program (VASQIP) data composed the VASQIP cohort. Data were analyzed between December 9, 2021, and September 18, 2023.

Exposures

Primary TKA as well as demographic, clinical, and perioperative factors.

Main Outcomes and Measures

Incident hospitalization with early, delayed, or late PJI. Incidence rate (events per 10 000 person-months) was measured in 3 postoperative periods: early (≤3 months), delayed (between >3 and ≤12 months), and late (>12 months). Unadjusted Poisson regression was used to estimate incidence rate ratios (IRRs) with 95% CIs of early and delayed PJI compared with late PJI. The frequency of organisms isolated from synovial or operative tissue culture results of PJIs during each postoperative period was identified. A piecewise exponential parametric survival model was used to estimate IRRs with 95% CIs associated with demographic and clinical factors in each postoperative period.

Results

The 79 367 patients (median (IQR) age of 65 (60-71) years) in the overall cohort who underwent primary TKA included 75 274 males (94.8%). A total of 1599 PJIs (2.0%) were identified. The incidence rate of PJI was higher in the early (26.8 [95% CI, 24.8-29.0] events per 10 000 person-months; IRR, 20.7 [95% CI, 18.5-23.1]) and delayed periods (5.4 [95% CI, 4.9-6.0] events per 10 000 person-months; IRR, 4.2 [95% CI, 3.7-4.8]) vs the late postoperative period (1.3 events per 10 000 person-months). Staphylococcus aureus was the most common organism isolated overall (489 [33.2%]); however, gram-negative infections were isolated in 15.4% (86) of early PJIs. In multivariable analyses, hepatitis C virus infection, peripheral artery disease, and autoimmune inflammatory arthritis were associated with PJI across all postoperative periods. Diabetes, chronic kidney disease, and obesity (body mass index of ≥30) were not associated factors. Other period-specific factors were identified.

Conclusions and Relevance

This cohort study found that incidence rates of PJIs were higher in the early and delayed vs late post-TKA period; there were differences in microbiological cultures and factors associated with each postoperative period. These findings have implications for postoperative antibiotic use, stratification of PJI risk according to postoperative time, and PJI risk factor modification.

Knee Arthrodesis: An Analysis of Surgical Risk Factors and Complications Using a National Database

Background

Knee arthrodesis is predominantly a salvage procedure. In present time, knee arthrodesis is mostly considered for cases of unreconstructable failed total knee arthroplasty after prosthetic joint infection or trauma. Knee arthrodesis has shown better functional outcomes than amputation for these patients but has a high complication rate. The purpose of this study was to characterize the acute surgical risk profile of patients undergoing a knee arthrodesis for any indication.

Methods

The American College of Surgeons National Surgical Quality Improvement Program database was queried to determine 30-day outcomes after knee arthrodesis between 2005 and 2020. Demographics, clinical risk factors, and postoperative events were analyzed, along with reoperation and readmission rates.

Results

A total of 203 patients that underwent a knee arthrodesis were identified. Forty-eight percent of patients had at least 1 complication. The most common complication was acute surgical blood loss anemia requiring a blood transfusion (38.4%), followed by organ space surgical site infection (4.9%), superficial surgical site infection (2.5%), and deep vein thrombosis (2.5%). Smoking was associated with higher rates of reoperation and readmission (odds ratio 9, P < .01, and odds ratio 6, P < .05).

Conclusions

Overall, knee arthrodesis is a salvage procedure that has a high rate of early postoperative complications and is most often performed in patients at higher risk. Early reoperation is strongly associated with a poor preoperative functional status. Smoking places patients at higher risk of early complications.

Impact of resident involvement on complication rates in revision total knee arthroplasty

Objectives

The number of revision total knee arthroplasty (TKA) procedures continues to rise, a direct consequence of the increase in primary TKA. The number of arthroplasty-trained orthopaedic surgeons has failed to increase at a corresponding rate, and the increased burden will ultimately fall on non-specialized orthopaedists. Resident involvement in primary TKA has not been found to increase postoperative complications, but revision TKA is more complex and the impact of resident involvement has not been well studied.

Methods

Using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database, this study identified 1834 revision TKA procedures between the years 2008 and 2012. Of these procedures, 863 included resident involvement. Demographic information, comorbidities, operative times, length of stay (LOS), and 30-day postoperative complications were stratified by resident and non-resident involvement and analyzed.

Results

Resident involvement was not associated with a significant increase in short-term complications. Operative times were significantly longer with resident involvement (147.50 min with resident involvement vs. 124.55 min without a resident, p < 0.001). Length of stay after procedures with resident involvement was higher by 0.34 days, but this did not reach significance (p = 0.061).

Conclusion

Resident involvement in revision total knee arthroplasty was associated with a significant increase in operative time; however, there were no significant increases in postoperative complication rates within 30 days. These findings support continued resident involvement in revision total knee arthroplasty cases and postoperative management.

Comparison of Operative Times in Primary Bilateral Total Knee Arthroplasty Performed by a Single Surgeon

Purpose: Prolonged operative time (OT) is associated with adverse complications after total knee arthroplasty (TKA). The purpose of this study was to determine whether preoperative factors, such as sex, age, body mass index, body weight (BW), body height, American Society of Anesthesiologists grade, tibiofemoral angle, hospital for special surgery scores, surgical side, surgical order, and calendar year of surgery, affect OT. Methods: One hundred and nineteen patients (238 knees) with osteoarthritis who underwent staged bilateral primary TKA performed by a single surgeon were evaluated. The medical records of 15 males and 104 females were retrospectively reviewed. All variables were expressed as median (interquartile range). Results: The OT for all TKAs was 57 min (51, 65). The OT on the left side (59 min (52−67)) was longer than that on the right side (55 min (50−62)) (p = 0.015). Multiple regression analysis revealed that longer OT was related to BW (β = 0.488, p < 0.001), calendar year of surgery (β = −0.218, p< 0.001), and operative side (β = −0.151, p = 0.007). The Jonckheere−Terpstra test showed a trend toward decreasing OT with calendar year on the left side (p = 0.037) (surgeon’s non-dominant side), but not on the right (p = 0.795). Body height, BW, and body mass index showed weak correlations (r = 0.212, p = 0.001; r = 0.352, p < 0.001; r = 0.290, p < 0.001, respectively) with OT. Conclusion: Patients with a large physique, and especially obesity, with an affected knee on the surgeon’s non-dominant side may require a longer OT; OT decreased over time.

Total Knee Arthroplasty, All-in-One versus Four-in-One Femoral Cutting Jig System: A Comparison Study

Background. Total knee arthroplasty (TKA) is often indicated for end-stage knee osteoarthritis management. The posterior-stabilized (PS) implant is one of the TKA implants with various component designs, including femoral component cutting jigs. However, little is known about how the differences in cutting jig designs affect the outcomes. This study aims to compare the radiographic and functional outcomes of the patients who underwent cemented TKA using all-in-one and four-in-one femoral component PS implants. Methods. A retrospective comparative study assessed patients who underwent cemented TKA using PS implants from 2018 to 2019. The patients were divided into all-in-one and four-in-one groups. Demographic data, surgery duration, postoperative radiological findings after one week, and functional outcomes after two years were collected and compared. Results. A total of 96 patients were included in the study, 55 patients were in all-in-one sample, and 41 patients were in four-in-one sample. The majority of the patients in both groups were female, aged >60 years old, overweight (BMI ≥ 25), and presented with an ASA score of II. We found significantly shorter surgery duration in the all-in-one group compared to the four-in-one group (128.00 ± 36.24 vs. 210.61 ± 57.54, $p=0.000$ ). The four-in-one group and the all-in-one group showed the insignificant difference in α, β, δ, and γ angles ( $p=0.476$ , 0.273, 0.594, and 0.818). The functional outcomes (SF-12, KSS, and KOOS) showed insignificant differences. Conclusion. There is no differentiation for the postsurgery functional and radiological outcomes between all-in-one and four-in-one implants.

Operative Time and Risk of Surgical Site Infection and Periprosthetic Joint Infection: A Systematic Review and Meta-Analysis

BACKGROUND

The purpose of this study was to perform a systematic review and meta-analysis on the association between operative time and peri-prosthetic joint infection (PJI) after primary total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

PubMed, Embase, and Cochrane CENTRAL databases were searched for relevant articles dating 2000-2020. Relationship of operative time and PJI rate in primary total joint arthroplasty (TJA) was evaluated by pooled odds ratios (OR) and 95% confidence intervals.

RESULTS

Six studies were identified for meta-analysis. TJA lasting greater than 120 minutes had greater odds of PJI (OR, 1.63 [1.00-2.66], p=0.048). Similarly, there were greater odds of PJI for TJA procedures lasting greater than 90 minutes (OR, 1.65 [1.27-2.14]; p<0.001). Separate analyses of TKA (OR, 2.01 [0.76-5.30]) and THA (OR, 1.06 [0.80-1.39]) demonstrated no difference in rates of PJI in cases of operative time ≥ 120 minutes versus cases < 120 minutes (p>0.05 for all). Using any surgical site infection (SSI) as an endpoint, both TJA (OR, 1.47 [1.181.83], p<0.001) and TKA (OR, 1.50 [1.08-2.08]; p=0.016) procedures lasting more versus less than 120 minutes demonstrated significantly higher odds of SSI.

CONCLUSION

Following TJA, rates of SSI and PJI are significantly greater in procedures ≥120 minutes in duration relative to those < 120 minutes. When analyzing TKA separately, higher rates of SSI were observed in procedures ≥ 120 minutes in duration relative to those <120 minutes. Rates of PJI in TKA or THA procedures alone were not significantly impacted by operative time. Level of Evidence: V.

The lifetime revision risk of unicompartmental knee arthroplasty

AIMS

Unicompartmental knee arthroplasty (UKA) has a higher risk of revision than total knee arthroplasty (TKA), particularly for younger patients. The outcome of knee arthroplasty is typically defined as implant survival or revision incidence after a defined number of years. This can be difficult for patients to conceptualize. We aimed to calculate the 'lifetime risk' of revision for UKA as a more meaningful estimate of risk projection over a patient's remaining lifetime, and to compare this to TKA.

METHODS

Incidence of revision and mortality for all primary UKAs performed from 1999 to 2019 (n = 13,481) was obtained from the New Zealand Joint Registry (NZJR). Lifetime risk of revision was calculated for patients and stratified by age, sex, and American Society of Anesthesiologists (ASA) grade.

RESULTS

The lifetime risk of revision was highest in the youngest age group (46 to 50 years; 40.4%) and decreased sequentially to the oldest (86 to 90 years; 3.7%). Across all age groups, lifetime risk of revision was higher for females (ranging from 4.3% to 43.4% vs males 2.9% to 37.4%) and patients with a higher ASA grade (ASA 3 to 4, ranging from 8.8% to 41.2% vs ASA 1 1.8% to 29.8%). The lifetime risk of revision for UKA was double that of TKA across all age groups (ranging from 3.7% to 40.4% for UKA, and 1.6% to 22.4% for TKA). The higher risk of revision in younger patients was associated with aseptic loosening in both sexes and pain in females. Periprosthetic joint infection (PJI) accounted for 4% of all UKA revisions, in contrast with 27% for TKA; the risk of PJI was higher for males than females for both procedures.

CONCLUSION

Lifetime risk of revision may be a more meaningful measure of arthroplasty outcomes than implant survival at defined time periods. This study highlights the higher lifetime risk of UKA revision for younger patients, females, and those with a higher ASA grade, which can aid with patient counselling prior to UKA. Cite this article: Bone Joint J 2022;104-B(6):672-679.

Risk factors for prosthetic joint infections following total hip arthroplasty based on 33,337 hips in the Finnish Arthroplasty Register from 2014 to 2018

Background and purpose - Periprosthetic joint infection (PJI) is a devastating complication and more information on risk factors for PJI is required to find measures to prevent infections. Therefore, we assessed risk factors for PJI after primary total hip arthroplasty (THA) in a large patient cohort.Patients and methods - We analyzed 33,337 primary THAs performed between May 2014 and January 2018 based on the Finnish Arthroplasty Register (FAR). Cox proportional hazards regression was used to estimate hazard ratios with 95% confidence intervals (CI) for first PJI revision operation using 25 potential patient- and surgical-related risk factors as covariates.Results - 350 primary THAs were revised for the first time due to PJI during the study period. The hazard ratios for PJI revision in multivariable analysis were 2.0 (CI 1.3-3.2) for ASA class II and 3.2 (2.0-5.1) for ASA class III-IV compared with ASA class I, 1.4 (1.1-1.7) for bleeding > 500 mL compared with < 500 mL, 0.4 (0.2-0.7) for ceramic-on-ceramic bearing couple compared with metal-on-polyethylene and for the first 3 postoperative weeks, 3.0 (1.6-5.6) for operation time of > 120 minutes compared with 45-59 minutes, and 2.6 (1.4-4.9) for simultaneous bilateral operation. In the univariable analysis, hazard ratios for PJI revision were 2.3 (1.7-3.3) for BMI of 31-35 and 5.0 (3.5-7.1) for BMI of > 35 compared with patients with BMI of 21-25.Interpretation - We found several modifiable risk factors associated with increased PJI revision risk after THA to which special attention should be paid preoperatively. In particular, high BMI may be an even more prominent risk factor for PJI than previously assessed.

Techniques and Strategies to Optimize Efficiencies in the Office and Operating Room: Getting Through the Patient Backlog and Preserving Hospital Resources

The effects of the coronavirus disease 2019 pandemic are pervasive and have decreased the volume of hip and knee arthroplasty procedures since the mandated cessation of elective surgical procedures at the height of the pandemic in early 2020. Therefore, a backlog of patients in need of these elective procedures is a probable consequence and increased productivity and efficiency in patient care delivery is essential now and into the future. This article outlines multiple strategies and techniques to develop and optimize efficiency in the hip and knee arthroplasty practice. Techniques for increasing surgical efficiency are detailed, along with perioperative strategies in the hospital, ambulatory surgery center, and office settings are outlined and discussed.

Platelet Deficiency Represents a Modifiable Risk Factor for Periprosthetic Joint Infection in a Preclinical Mouse Model

BACKGROUND

Well known for their hemostatic function, platelets are increasingly becoming recognized as important immunomodulators. The purpose of the present study was to assess the impact of platelet depletion on antimicrobial host defense in a mouse model of periprosthetic joint infection (PJI).

METHODS

Thrombocytopenia (TCP) was induced in C57BL/6 mice with use of a selective antibody against platelet CD41 (anti-CD41). Whole blood from pre-treated mice was incubated with Staphylococcus aureus to assess antimicrobial efficacy with use of bioluminescent imaging, quantitative histological staining, and colony forming unit (CFU) quantification. In parallel, untreated heterologous platelets were added to TCP blood to assess potential rescue of antimicrobial efficacy. In vivo, TCP and control mice underwent placement of a titanium implant in the femur inoculated with bioluminescent Xen36 S. aureus. Longitudinal bioluminescent imaging was performed postoperatively to quantify the evolution of bacterial burden, which was confirmed via assessment of S. aureus CFUs on the implant and in peri-implant tissue on postoperative day (POD) 28.

RESULTS

Anti-CD41 treatment resulted in significant dose-dependent reductions in platelet count. Ex vivo, platelet-depleted whole blood demonstrated significantly less bacterial reduction than control blood. These outcomes were reversed with the addition of untreated rescue platelets. In vivo, infection burden was significantly higher in TCP mice and was inversely correlated with preoperative platelet count (r2 = 0.63, p = 0.037). Likewise, CFU quantification on POD28 was associated with increased bacterial proliferation and severity of periprosthetic infection in TCP mice compared with controls.

CONCLUSIONS

Thrombocytopenia resulted in an increased bacterial burden both ex vivo and in vivo in a mouse model of PJI.

CLINICAL RELEVANCE

In orthopaedic patients, deficiencies in platelet quantity or function represent an easily modifiable risk factor for PJI.

Analysis of the relationship between surgeon procedure volume and complications after total knee arthroplasty using a propensity-matched cohort study

Objectives

This study aimed to identify a threshold in annual surgeon volume associated with increased risk of revision (for any cause) and deep infection requiring surgery following primary elective total knee arthroplasty (TKA).

Design

A propensity score matched cohort study.

Setting

Ontario, Canada.

Participants

169 713 persons who received a primary TKA between 2002 and 2016, with 3-year postoperative follow-up.

Main outcome measures

Revision arthroplasty (for any cause), and the occurrence of deep surgical infection requiring surgery.

Results

Based on restricted cubic spline analysis, the threshold for increased probability of revision and deep infection requiring surgery was <70 cases/year. After matching of 51 658 TKA recipients from surgeons performing <70 cases/year to TKA recipients from surgeons with greater than 70 cases/year, patients in the former group had a higher rate of revision (for any cause, 2.23% (95% Confidence Interval (CI) 1.39 to 3.07) vs 1.70% (95% CI 0.85 to 2.55); Hazard Ratio (HR) 1.33, 95% CI 1.21 to 1.47, p<0.0001) and deep infection requiring surgery (1.29% (95% CI 0.44 to 2.14) vs 1.09% (95% CI 0.24 to 1.94); HR 1.33, 95% CI 1.17 to 1.51, p<0.0001).

Conclusions

For primary TKA recipients, cases performed by surgeons who had performed fewer than 70 TKAs in the year prior to the index TKA were at 31% increased relative risk of revision (for any cause), and 18% increased relative risk for deep surgical infection requiring surgery, at 3-year follow-up.

Revision for periprosthetic joint infection rate stratified by seasonality of operation in a national population of total and unicompartmental knee arthroplasty patients: a register-based analysis

Aim: The aim of this study was to investigate whether the revision rate for periprosthetic joint infection (PJI) depends on the season of the primary procedure using a national population of knee arthroplasty (KA) patients. Seasonal variation of some surgical procedures has been observed to impact subsequent infection risks, with a higher risk of revision for surgeries performed during summer, but an analysis of PJI rates based on a national arthroplasty register has yet to be completed. We hypothesized that an increased risk of revision due to PJI could be demonstrated in a national population when primary surgery was performed during the summer. Methods: The Danish Knee Arthroplasty Registry (DKR) was used to determine the risk of revision due to PJI within 2 years after primary surgery. All primary KA procedures between 1 January 1997 and 31 December 2014 and revisions until 31 December 2016 were identified. Smoothing spline regression was used to identify possible seasonal pattern effects of the primary procedure on revision risk, and logistic regression was used to calculate risk of infection differences between seasons. Results: A total number of 124 809 primary procedures was registered in the study period. After excluding duplicates and matching primary procedures with the first revisions within 2 years after the primary procedure, 3391 were identified. Of these, 348 cases were recorded with an indication of deep infection requiring revision. Spline regression analyses did not demonstrate any clear seasonal pattern of the primary procedure regarding the risk of revision for infection or any other cause. Logistic regression found a decreased risk of revision for infection when the primary procedure was performed during the summer in the years 1997 to 2005, no influence on the risk of revision for infection in 2005 to 2012, and an increased risk of revision for infection following summer procedures during the years 2013 to 2014. Conclusion: It was not possible to demonstrate a consistent seasonal variation of the risk of revision for PJI following primary KA. This is most likely because the underlying etiologies for PJI are not subject to seasonal variation.

Complication Rates and the Benefits of Neuraxial Anesthesia in the Patient With High Comorbidity Burden Undergoing Primary Total Joint Arthroplasty

BACKGROUND

The American Society of Anesthesiologists physical status classification 4 (ASA PS 4) comprises patients with "severe systemic disease that is a constant threat to life." The purpose of this study is to conduct a retrospective analysis to report the rate of complications in the ASA PS 4 patients who undergo elective total joint arthroplasty (TJA). In addition, we report whether neuraxial anesthesia is associated with improved outcomes compared to general anesthesia in these patients.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program registry was used to extract patient records. The study population included patients aged ≥18 years who underwent TJA from 2014 to 2016 and who were classified as ASA PS 4. To measure differences in outcomes and patient characteristics, we used chi-squared tests. Odds ratios (ORs) and their 95% confidence intervals (CIs) were reported for all covariates. A P value of <.01 was selected.

RESULTS

Among the patients who were ASA PS 4, 58 (1.4%) experienced 30-day mortality, 349 (8.2%) experienced 30-day readmission, 271 (6.3%) had a postoperative complication, and 504 (11.8%) required a transfusion. Those receiving neuraxial anesthesia compared to general anesthesia had lower odds of 30-day mortality (OR, 0.24; 95% CI, 0.12-0.49; P = .0001) and lower odds of perioperative transfusion (OR, 0.53; 95% CI 0.45-0.65; P < .0001).

CONCLUSION

The elevated risks for ASA PS 4 patients undergoing TJA may be too high to justify surgery. Neuraxial anesthesia is a reasonable alternative to general anesthesia if pursuing TJA in patients with a very high comorbidity burden.

Infection Risk-Adjusted Antibiotic Prophylaxis Strategies in Arthroplasty: Short Review of Evidence and Experiences of a Tertiary Center in Spain

There is growing body of evidence that important patient-, procedure- and pathogen-related factors are linked to higher risks for prosthetic joint infections (PJI) following arthroplasty surgeries. The prior identification and optimization of such risk factors is considered paramount to minimize the incidence of these infections. Without any doubt, antibiotic prophylaxis remains one of the cornerstones among all preventive measures. However, the ideal antibiotic prophylaxis is still in debate and discussions have emerged, whether certain situations deserve adjustments or variations of the standard protocol taking into account antibiotic resistance surveillance data and patient risk factors for infections. This review aims to provide the reader with an overview of possible antibiotic prophylaxis strategies in response to these risks and discusses the clinical experiences so far obtained. We further present preliminary evidence that the use of a reinforced local antibiotic prophylaxis regimen with high-dose dual antibiotic-loaded bone cement may be an effective and easy-to-apply option in patients at high infection risks.

Failure After 2-Stage Exchange Arthroplasty for Treatment of Periprosthetic Joint Infection: The Role of Antibiotics in the Cement Spacer

BACKGROUND

Failure after a 2-stage exchange surgery for periprosthetic joint infection (PJI) is high. Previous studies demonstrated that positive cultures at reimplantation are associated with failure afterward. The aim of this multicenter study was to define the role of antibiotics in the cement spacer in relation to reimplantation cultures and subsequent failure.

METHODS

We retrospectively evaluated 2-stage exchange procedures between 2000 and 2015. Culture-negative PJIs, cases in which no cultures were obtained during reimplantation, and cases without data on cement spacers were excluded.

RESULTS

Three hundred forty-four cases were included. The rate of positive cultures during reimplantation was 9.5% for cement spacers containing a glycopeptide (27/284) (with or without an aminoglycoside) vs 21.7% for those containing monotherapy with an aminoglycoside (13/60) (P = .008), and was mostly attributed by a reduction in coagulase-negative staphylococci (CoNS) (17% vs 2%, P < .001). The failure rate was >2-fold higher at 40.0% (16/40) in cases with positive cultures at reimplantation compared to 15.8% (48/304) for those with negative cultures (P < .001). Overall, a glycopeptide in the cement spacer was not associated with a lower failure rate (18% vs 23%, P = .3), but was associated with lower failure due to CoNS (2.5% vs 13.3%, P < .001).

CONCLUSIONS

In a 2-stage exchange procedure for PJI, adding a glycopeptide to the cement spacer reduces the rate of positive cultures during reimplantation and is associated with a lower failure rate due to CoNS afterward.

Total knee arthroplasty: A single centre review at 10 years of follow-up

Background:

Total knee arthroplasty is a common procedure for treatment of various non-infective arthritis. This study reviewed total knee arthroplasty cases up to 10 years of follow-up for the survival rate, reasons of revision and associated perioperative risk factors for revision.

Methods:

All cases to total knee arthroplasty performed in a single centre in the years 2007 and 2008 were reviewed. A total of 227 cases of total knee arthroplasty were performed during the 2-year period, with 156 cases followed up to 10 years. Perioperative information, follow-up information and information of possible complications were obtained.

Results:

The survival rate of total knee arthroplasty in this study is 98.2% at 5 years and 94.2% at 10 years of follow-up. The early post-operative complication rate was low, and majority of cases had improvement of function at 1 year after the operation. Early post-operative infection rate was low at 0.4%, and overall infection up to 10 years of follow-up was also low at 4.4%. Ten cases had undergone revision of arthroplasty by 10 years after operation.

Conclusion:

The survival rate of total knee replacement was high. The revision rate and infection rates were low up to 10 years of follow-up. The most common reasons of revision arthroplasty were infection and aseptic loosening. Cases which required revision arthroplasty had significantly longer operative duration compared with cases without revision at 10 years of follow-up ( p = 0.01).

BMI is a Better Predictor of Periprosthetic Joint Infection Risk Than Local Measures of Adipose Tissue After TKA

BACKGROUND

Both body mass index (BMI) and local measures of adiposity at the surgical site have been identified as independent risk factors for periprosthetic joint infection (PJI) (periprosthetic joint infection) after total knee arthroplasty (TKA). We aimed to 1) evaluate previously used measures of assessing knee adiposity and 2) determine the best measure for predicting both surgical duration and PJI after TKA.

METHODS

We performed a multicentre retrospective review of 4745 patients who underwent primary TKA between January 2013 and December 2016. Patient demographic information, surgical duration and postoperative infection status within one year were obtained. Preoperative weight-bearing AP and lateral x-rays were analyzed to determine prepatellar adipose thickness, bony width of the tibial plateau, and total soft tissue knee width. The knee adipose index (KAI) was calculated from the ratio of bone to total knee width.

RESULTS

We observed substantial variability in both local measures of adiposity compared with BMI. Neither measure of local knee adipose showed a significant correlation with PJI risk. By contrast, there was a strong correlation between PJI risk and BMI >35 (odds ratio 2.9, 95% CI 1.4-6.1). Surgical duration increased with both BMI and measures of local adipose tissue (KAI and prepatellar fat thickness).

CONCLUSION

Local adipose deposition varies greatly for any given BMI. In this study, BMI was a better predictor of PJI after TKA than local measures of knee adipose tissue.

Time-dependent surgical instrument contamination begins earlier in the uncovered table than in the covered table

PURPOSE

Time-dependent surgical instrument contamination and the effect of covering during arthroplasty have not been investigated. This study aimed to evaluate time-dependent contamination of surgical instruments and the effect of covering on contamination as well as to perform bacterial typing of contaminated samples. The hypothesis was that covering the surgical instruments would decrease contamination rates.

METHODS

Sixty patients who underwent total knee arthroplasty were randomized and divided into two groups: surgical instruments covered with a sterile towel or surgical instruments left uncovered. K-wires were used to extract microbiological samples. The K-wires were placed in a liquid culture medium at 0, 15, 30, 60, 90, and 120 min. After 24-h incubation period, samples from liquid cultures were cultured on blood agar using swabs. Samples with growth after 48 h were considered contaminated. Microscopic, staining, and biochemical properties were used for bacterial typing.

RESULTS

Bacterial growth started after 30 and 60 min in the uncovered and covered groups, respectively. An increase in the number of K-wires contaminated with time was detected. At least 10,000 CFU/mL bacterial load was observed in the culture samples. Contamination was more significant in the uncovered group. A statistically significant difference in contamination was found between the uncovered and covered groups at 30-, 60-, 90-, and 120 min (p = 0.035, p = 0.012, p = 0.024, and p = 0.037, respectively). The most common bacteria on the contaminated instruments were coagulase-negative Staphylococci (60.4%), Staphylococcus aureus (22.9%), and Streptococcus agalactia (16.7%), respectively.

CONCLUSION

The risk of contamination increases with time. However, it may decrease if surgical instruments are covered. In the clinical practice, empiric antibiotic regimens based on the type of identified microorganisms in this study may be developed for postoperative periprosthetic joint infection prophylaxis.

LEVEL OF EVIDENCE

Prognostic, Level II.

Comparable outcomes in mini-midvastus versus mini-medial parapatellar approach in total knee arthroplasty: a meta-analysis and systematic review

BACKGROUND

Minimally invasive surgery (MIS) techniques in total knee arthroplasties (TKA) have gained popularity over conventional techniques due to benefits of hastened recovery and reduced complications. There are a variety of MIS techniques available and two most common techniques currently employed are the mini-midvastus (mMV) and mini-medial parapatellar (mMPP) approaches. This meta-analysis aims to compare the clinical outcomes and peri-operative parameters between mMV and mMPP in TKA in order to determine the presence of a superior technique.

METHODS

A multi-database search was performed according to PRISMA guidelines. Data from studies comparing clinical outcomes and peri-operative parameters between mMV and mMPP approaches in TKA were extracted and analysed.

RESULTS

A total of five randomized controlled trials were included for analysis, consisting of 190 mMV and 189 mMPP knees. Clinically unimportant differences were noted in blood loss and surgical time between the groups (5 mL less blood loss and 7 min less surgical time in mMV, P < 0.001). There was no statistically significant difference between both groups for Knee Society Score at 1 and 2 years, range of motion at 1 and 2 years, incision length or incidence of lateral retinacular release (all non-significant, P > 0.05).

CONCLUSION

The mMV and mMPP MIS TKA approaches have equivalent clinical outcomes. Despite a statistically significant longer operative time and higher mean blood loss in mMV than mMPP approach, clinically significant difference was not demonstrated. Both mMV and mMPP MIS techniques are reliable and safe to perform in TKA.

Predictive factors for longer operative times in patients with medial knee osteoarthritis undergoing total knee arthroplasty

Background

Prolonged operative time has frequently been implicated as a risk factor for various complications after total knee arthroplasty (TKA). We aimed to determine whether preoperative factors such as sex, age, body mass index (BMI), prosthetic design, tibiofemoral angle (TFA), range of motion, coronal laxity, Hospital for Special Surgery score and periarticular bone mineral density (BMD) affect operative time.

Methods

We evaluated 164 patients (187 knees) with medial osteoarthritis who underwent primary TKA performed by a single surgeon. The medical records of 27 males and 137 females (median age of 77 and 72 years, respectively) were retrospectively reviewed. TFA was measured on non-weightbearing, standard radiographs. We used dual-energy X-ray absorptiometry to measure BMD, and an arthrometer to evaluate total coronal laxity in each patient.

Results

According to univariate analyses, there was a weak positive correlation between BMI and operative time (r = 0.265, p < 0.001), between TFA and operative time (r = 0.235, p = 0.001) and between BMD of the femur and tibia and operative time (r = 0.280, p < 0.001, r = 0.286, p < 0.001, respectively). No significant correlations were found between the other factors and operative time. Based on multivariate analyses, only BMD of the tibia and TFA were significantly correlated with operative time (β = 0.418, p < 0.001 and β = 0.182, p = 0.007, respectively).

Conclusions

TFA and BMD of the tibia were the variables more strongly correlated with operative time. Surgeons should recognize preoperatively that patients who have increased TFA, higher periarticular BMD, and higher BMI may have longer operative times.

Level of evidence

Level IV retrospective study.

Primary constrained and hinged total knee arthroplasty: 2- and 5-year revision risk compared with unconstrained total knee arthroplasty: a report on 401 cases from the Norwegian Arthroplasty Register 1994-2017

Background and purpose - The number of primary, highly constrained knee arthroplasty implants has increased with a theoretically increased risk of early failure. Therefore we analyzed the risk of all revision following total knee arthroplasty (TKA) in patients receiving a hinged or condylar constrained knee (CCK) compared with a conventional unconstrained TKA. Patients and methods - The analyses included 401 primary highly constrained or hinged implants from 1994 to 2017. Kaplan-Meier survival curves were used to evaluate time to first revision with a maximum follow-up of 20 years. Cox regression was used to calculate hazard ratio (HR) comparing condylar constrained knee (CCK), hinged, and unconstrained TKA. Results - Kaplan-Meier estimated prosthesis survival after 2 years was 94.8% (95% CI 91.4-98.2) and 93.5% after 5 years for the primary CCK and 91.0% (CI 86.6-95.4) after 2 years and 85.5% after 5 years for the primary hinged TKA. Adjusted for sex, age groups, diagnosis, time period, previous surgery, and surgery time HR was 1.4 (CI 0.8-2.3) for the CCK and 2.4 (CI 1.6-3.7) for the hinged implants. The most common cause of revision in hinged implants was infection: 14 of 22 revisions. When excluding infection as revision cause, there were no differences in survival between the implant types. Estimated survival excluding infection revisions at 5 years was 96% for unconstrained, CCK, and hinged primary TKA implants. Interpretation - Primary rotating hinge total knee arthroplasty had a higher risk of revision compared with conventional TKA after 2 and 5 years' follow-up. Infection was the most common cause of revision. When excluding infection revisions from the survival analysis, hinged and CCK implants had similar performance to unconstrained TKA.

The cost of implanting a cemented versus cementless total knee arthroplasty

Aims

The aim of this study was to compare the actual cost of a cemented and cementless total knee arthroplasty (TKA) procedure.

Materials and Methods

The cost of operative time, implants, cement, and cementing accessories were included in the overall cost of the TKA procedure. Operative time was determined from a previously published study comparing cemented and cementless implants of the same design. The cost of operative time, implants, cement, and cementing accessories was determined from market and institutional data.

Results

Mean operative time for cemented TKA was 11.6 minutes longer for cemented TKA than cementless TKA (93.7 minutes (sd 16.7) vs 82.1 minutes (sd 16.6); p = 0.001). Using a conservative published standard of $36 per minute for operating theatre time cost, the total time cost was $418 higher for cementing TKA. The cost of cement and accessories ranged from $170 to $625. Overall, the calculated cost of cemented TKA is $588 to $1043, depending on technique. The general increased charge for cementless TKA implants over cemented TKA implants was $366.

Conclusion

The overall procedural cost of implanting a cementless TKA is less than implanting a cemented TKA. Cost alone should not be a barrier to using cementless TKA. Cite this article: Bone Joint J 2019;101-B(7 Supple C):61–63

Is Operative Time a Predictor for Post-Operative Infection in Primary Total Knee Arthroplasty?

BACKGROUND

The purpose of this study is to identify factors affecting operative times and to evaluate the associations of operative times with prosthetic joint infections (PJIs) and surgical site infections (SSIs) in primary total knee arthroplasty.

METHODS

A total of 11,840 primary total knee arthroplasties with a mean 2-year post-operative follow-up were studied. Operative times were analyzed both as categorical and continuous variables. Associations with PJIs and SSIs were evaluated with univariate and multivariate analyses to adjust for gender, age, body mass index, Charlson Comorbidity Index, year of surgery, antibiotic cement use, and hospital/surgeon volume.

RESULTS

The longest cases (>121 minutes) were associated with patients who were younger (P < .001) and had a higher body mass index (P < .001). PJI rates were higher in cases >121 minutes (1.4%) compared to those <85 minutes (0.3%, P < .001). SSI rates were also highest (3.8%) in cases >121 minutes (P < .001). Cases complicated by PJIs (135 ± 47 minutes) had longer mean operative times compared to non-infected cases (105 ± 32 minutes, P < .001). Patients with subsequent SSIs also had longer mean operative times (P < .001). Multivariate analyses revealed an 18% increased risk for PJIs and an 11% increased risk for SSIs for every 15-minute increase in operative time.

CONCLUSION

Identifying risk factors for infection that are as easily measurable and modifiable as procedure duration can aid in risk-stratifying post-operative surveillance. This study demonstrated that longer operative times were an independent predisposing factor for both PJIs and SSIs even after accounting for patient and procedure-related factors.

Duration of antibiotic treatment and risk of recurrence after surgical management of orthopaedic device infections: a multicenter case-control study

Background

Device-related infections in orthopaedic and trauma surgery are a devastating complication with substantial impact on morbidity and mortality. Systemic suppressive antibiotic treatment is regarded an integral part of any surgical protocol intended to eradicate the infection. The optimal duration of antimicrobial treatment, however, remains unclear. In a multicenter case-control study, we aimed at analyzing the influence of the duration of antibiotic exposure on reinfection rates 1 year after curative surgery.

Methods

This investigation was part of a federally funded multidisciplinary network project aiming at reducing the spread of multi-resistant bacteria in the German Baltic region of Pomerania. We herein used hospital chart data from patients treated for infections of total joint arthroplasties or internal fracture fixation devices at three academic referral institutions. Subjects with recurrence of an implant-related infection within 1 year after the last surgical procedure were defined as case group, and patients without recurrence of an implant-related infection as control group. We placed a distinct focus on infection of open reduction and internal fixation (ORIF) constructs. Uni- and multivariate logistic regression analyses were employed for data modelling.

Results

Of 1279 potentially eligible patients, 269 were included in the overall analysis group, and 84 contributed to an extramedullary fracture-fixation-device sample. By multivariate analysis, male sex (odds ratio [OR] 2.06, 95% confidence interval [CI] 1.08 to 3.94, p = 0.029) and facture fixation device infections (OR 2.05, 95% CI 1.05 to 4.02, p = 0.036) remained independent predictors of reinfection. In the subgroup of infected ORIF constructs, univariate point estimates suggested a nearly 60% reduced odds of reinfection with systemic fluoroquinolones (OR 0.42, 95% CI 0.04 to 2.46) or rifampicin treatment (OR 0.41, 95% CI 0.08 to 2.12) for up to 31 days, although the width of confidence intervals prohibited robust statistical and clinical inferences.

Conclusion

The optimal duration of systemic antibiotic treatment with surgical concepts of curing wound and device-related orthopaedic infections is still unclear. The risk of reinfection in case of infected extramedullary fracture-fxation devices may be reduced with up to 31 days of systemic fluoroquinolones and rifampicin, although scientific proof needs a randomized trial with about 1400 subjects per group. Concerted efforts are needed to determine which antibiotics must be applied for how long after radical surgical sanitation to guarantee sustainable treatment success.

Readmission Following Revision Total Knee Arthroplasty: An Institutional Cohort

Purpose: Total knee arthroplasty (TKA) is the most common joint replacement surgery performed in the United States. Given the aging and increasingly comorbid patient populations undergoing these procedures, complication rates and the need for subsequent hospital readmission are only expected to rise. It is, therefore, crucial to investigate the risk factors leading to readmission in order to improve patient outcomes. The purpose of this study is to identify significant risk factors for readmission following revision TKA procedures.

Methods: Patients undergoing revision TKA were identified at our institution from 2006-2017. The primary outcome was hospital readmission after revision TKA. Patient demographics, comorbidities, and postoperative complications were recorded and compared between readmitted and non-readmitted patients.

Results: Forty-five (26.2%) of the 171 cases were readmitted following revision TKA. The leading diagnoses at readmission varied from arthrofibrosis in 28.9% of patients, implant infection in 22.2% of patients, and implant failure in 20.0% of patients. Male gender was found to be a significant independent variable for readmission. This study also found that 51.1% of all readmitted patients continued to have complaints that required additional hospital readmissions. The average number of total readmissions was 2.1 per readmitted patient.

Conclusion: This study was successful in identifying variables associated with readmission following revision TKA, as well as presenting information regarding the diagnoses associated with readmission. Our data also showed that if a patient was readmitted after revision TKA, it was likely that they would be admitted again. Due to the increasing prevalence and cost of these procedures, further studies are needed to better understand the risk factors and comorbidities leading to readmission in order to improve the perioperative care of these patients.

Comparison of Nonabsorbable and Absorbable Suture in Total Knee Arthroplasty

Background

Wound closure of KA is important for postoperative rehabilitation. At present there is still no consensus on the best wound closure technique for KA. We performed the present study to determine whether absorbable suture is better than nonabsorbable suture in total knee arthroplasty (TKA).

Material/Methods

A total of 180 patients who underwent TKA were divided into 3 groups: 80 cases of nonabsorbable suture, 50 cases of 2-0 absorbable suture, and 50 cases of 4-0 absorbable suture. The time required for closure, frequency of gauze change, length of stay in hospital, adverse events, range of motion (ROM) after 3 months postoperatively, and VAS score of wounds were calculated. Comparison was made to explore any significant differences between different groups.

Results

There were significant differences between the nonabsorbable group and the absorbable group with regards to closure time, frequency of gauze change, and hospital length of stay (LOS). Closure time was longer in the absorbable group than in the nonabsorbable group. Frequency of gauze change, hospital LOS, and adverse events were lower, and VAS was higher in the absorbable group. Closure time was longer in the 4-0 absorbable group than in the 2-0 group. There was no significant difference between the 4-0 group and 2-0 group in other variables. There was no significant difference in long-term ROM among all groups.

Conclusions

Absorbable suture in TKA reduces the incidence of fatty liquefaction, frequency of gauze change, and postoperative LOS. It improves the cosmetic appearance and overall reduces the economic cost. There was no significant effect on early and long-term functional ROM. In conclusion, absorbable suture can be used in TKA when appropriately indicated.